From what I've been able to tell, its mainly features and device compatibility that's different.
CM9's goal is bringing AOSP ICS to as many devices as possible
AOKP's goal seems to mainly be an enhanced AOSP ICS ROM for devices that already have ICS (Galaxy Nexus, Xoom, etc)

I would actually like to ask how the battery life on the Galaxy Nexus is?

On my Verizon Galaxy Nexus, its pretty meh to bad. In standby it doesn't too bad (it at least gets through the day) but the screen full on rapes the battery if your using it, even on low brightness. I can manage to get 2, maybe 3 hours of battery with the screen on (with a few hours of standby mind you). When its off, I can easily go 20+.

But everything else about the phone is too kickass for me to care too much, especially since a charger is normally not too far away. And if it isn't, I'm too busy to be using my phone anyway.

Looking to flash Codeworkx's CM9 on my GSII and deciding which way to pick, Nightly or Resurrection. Am I to assume Resurrection Edition is just a monthly updated and more stable version flashed via Odin instead of CWM?

Looking to flash Codeworkx's CM9 on my GSII and deciding which way to pick, Nightly or Resurrection. Am I to assume Resurrection Edition is just a monthly updated and more stable version flashed via Odin instead of CWM?

Ressurection Edition is just a different way to get CM9 on your device. Possibly easier/simpler if you didn't flash anything before.
Codeworkx releases a new one every month or so, but it's just built from the standard nightlies that you see on get.cm.

Noticed on the XDA thread for Codeworkx's CM9 it says to go with Ressurection if your bootloader is higher than LPH or unsure.......I fall into the unsure category since I'm on LP8 now. May as well go with it since I assume after flashing Ressurection Edition you can go with the Nightly builds and not have any issues.

Noticed on the XDA thread for Codeworkx's CM9 it says to go with Ressurection if your bootloader is higher than LPH or unsure.......I fall into the unsure category since I'm on LP8 now. May as well go with it since I assume after flashing Ressurection Edition you can go with the Nightly builds and not have any issues.

Wasn't LP8 still a beta, and LPH the first official ICS release? Don't take my word on it though, I don't remember it too good as I never flashed the Samsung ICS releases.
But yes, if you flash ressurection, you can use the CWM flashable nightly builds with no issue.